. Transactions. seems to behave in the same way, althoughthe rate of removal is a httle less rapid. Its retardation at the end is dueto the same causes. EDWARD L. FORD 399 Phosphorus.—The phosphorus removal-rate is constant to about 70 to75 per cent., when retardation sets in, and progressively increases, theline tending to parallel rather than intersect the 100 per cent. line. Thelong time required to remove phosphorus, as compared with silicon andmanganese, would make the lack of mobility at this stage a factor ofpractically no consequence; but, after the elimination of silicon, carbonicoxid
. Transactions. seems to behave in the same way, althoughthe rate of removal is a httle less rapid. Its retardation at the end is dueto the same causes. EDWARD L. FORD 399 Phosphorus.—The phosphorus removal-rate is constant to about 70 to75 per cent., when retardation sets in, and progressively increases, theline tending to parallel rather than intersect the 100 per cent. line. Thelong time required to remove phosphorus, as compared with silicon andmanganese, would make the lack of mobility at this stage a factor ofpractically no consequence; but, after the elimination of silicon, carbonicoxide begins to be formed; and (as Pourcel showed very clearly, in theearly days of the basic Bessemer process, in the discussion on the necessityfor the overblow to remove the phosphorus) phosphorus cannot beremoved from iron when CO is being formed intermolecularly in quantity;and no doubt the proportion of phosphorus removed is inversely relatedto the amount of CO formed, during a given period. True, the forma-. 25 30 35 40 45 50 55 60 TIME, MINUTES Fig. 3.—Removal of Metalloids in the Washing Process. tion of CO, by lowering the temperature of the bath, tends to stop itself;but it completely ceases only when the metal is so cool that it begins toset; and this, of course, impairs the fluidity necessary to bring new surfacesof metal in contact with the slag, in order to oxidize the small amount ofphosphorus left. We, therefore, finally reach a point of equilibrium whenthe CO formed just reduces the amount of phosphorus oxidized. If weincrease the heat of the furnace, to increase the fluidity of the metal, weincrease again the amount of CO that can form, and so are no betteroff. Sulphur.—Our theory of the elimination of sulphur I have never seenformulated and would hesitate to report it here, if I were not trying togive the rationale of the washing process, as we have known it. Even atquite a low temperature, sulphur appears to form sulphides, preferably 400 WASHED METAL to
Size: 2054px × 1216px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bo, bookcentury1800, bookdecade1870, booksubjectmineralindustries
